1. Field of the Invention
The present invention relates to an obstruction detection apparatus incorporated in a vehicle for detecting the distance from the vehicle to an obstruction and the position of the obstruction, for displaying data corresponding to the distance to the obstruction and the position of the obstruction to a driver of the vehicle on a Liquid Crystal (LC) display, and for sounding an alarm for the driver through an alarm device incorporated in the vehicle.
2. Description of the Prior Art
FIG. 22 is a plane view showing a plurality of sensors forming a conventional obstruction detection apparatus incorporated in a vehicle that has been disclosed in a Japanese patent document, namely the Japanese patent laid-open publication Number JP-A-62/59880. FIG. 23 is a block diagram showing a configuration of the conventional obstruction detection apparatus shown in FIG. 22. In FIG. 23, the reference number 1 designates an vehicle, the reference numbers 2 to 5 denote sensors arranged on each corner of the vehicle 1. Each of the sensors 2 to 5 is connected to each of detection circuits 6 to 9, each including an oscillator (omitted from FIG. 23). Each of the sensors 2 to 5 detects an obstruction independently and transfers data about the detected obstruction to a display device 10 placed near the driver. This display device 10 comprising a plurality of display sections corresponding to areas around the sensors 2 to 5. This display device 10 is capable of displaying a distance between the vehicle 1 and the obstruction by using the number of display bars or bar segments. For example, when an obstruction is near the sensor 2, namely, when the obstruction is at the front right section of the right hand side of the vehicle 1 and when the vehicle 1 is moving toward this obstruction, the sensor 2 and the detection circuit 6 detect the position of the obstruction and instructs that the most inside display bar in the display device 10 lights up. Then, when the vehicle 1 is near the obstruction, for example, it almost contacts the obstruction, the most outside display bar in the front right section in the display device 10 lights up in order to inform the most danger state to the driver.
The display bars forming the display device 10 to inform the distance between the vehicle 1 and the obstruction light up in steps toward the outside of the figure showing the vehicle 1, as shown in FIG. 23, when the vehicle 1 is moving toward the obstruction because the conventional obstruction detection apparatus in the vehicle 1 has the configuration described above. Accordingly, the conventional obstruction detection apparatus has a drawback that it is difficult for the driver of the vehicle 1 to recognize the distance between the vehicle 1 and the obstruction and the position of the obstruction easily and preciously in sensibility.
Furthermore, for example, when both the display bars corresponding to the sensor 4 of the rear right side and the sensor 5 of the rear left side light up simultaneously, it is difficult for the driver to recognize whether the obstruction is near the rear right side or the rear left side and it is also difficult for the driver to recognize the information regarding the actual position of the obstruction, and it takes a long time for the driver to recognize the correct position of the obstruction because the driver only watches the number of the display bars lighting up on the display device 10.